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super spud

macrumors member
Original poster
Nov 20, 2013
45
0
Hi all
Have been reading into the above topic to see if I really need the upgraded 21.5" imac or if I can get away with the base model. I do not game often but sometimes wotk with large pdf files in CAD which can really slow my work pc down. Is the dedicated card much better? I have done some reading on the topic but thr articles were from early periods and now wanted opinions now the dust has settled. Is there a relevant article on aandtech?

Much appreciated
 

yjchua95

macrumors 604
Apr 23, 2011
6,725
233
GVA, KUL, MEL (current), ZQN
No matter how you look at it, integrated graphics can never beat discrete graphics.

Go for the GT750M.

If you use AutoCAD or anything else from Autodesk, you'll also want to consider the i7, because the i7 has 8 threads, compared to the i5's 4.

And according to CPU-world.com, on average, i7s perform around 30% better than a similarly clocked i5, or higher-clocked i5 in multithreaded tasks or apps that support multithreading.
 

kaellar

macrumors 6502
Nov 12, 2012
441
17
If your CAD apps use OpenCL for computing, than Iris Pro will beat the **** out of 750m, so don't listen to the post above this one. 750m is much better for gaming. And that's true for gaming only.
 

yjchua95

macrumors 604
Apr 23, 2011
6,725
233
GVA, KUL, MEL (current), ZQN
Depends, really. Autodesk apps may also be CUDA-assisted, and if this is the case, the GT750M trounces the Iris.

Oh and on a side note, look up Anandtech's review on the Iris Pro, compared to the GT 650M. The GT750M is faster than the 650M by the way, but not significantly.
 

IA64

macrumors 6502a
Nov 8, 2013
552
66
Depends, really. Autodesk apps may also be CUDA-assisted, and if this is the case, the GT750M trounces the Iris.

Oh and on a side note, look up Anandtech's review on the Iris Pro, compared to the GT 650M. The GT750M is faster than the 650M by the way, but not significantly.

Nop, not really.... here you go :

http://www.anandtech.com/show/6993/intel-iris-pro-5200-graphics-review-core-i74950hq-tested/17

Iris pro is wiping the floor with the 650M.

I urge you to read the full article.
 

kaellar

macrumors 6502
Nov 12, 2012
441
17
Nop, not really.... here you go :

http://www.anandtech.com/show/6993/intel-iris-pro-5200-graphics-review-core-i74950hq-tested/17

Iris pro is wiping the floor with the 650M.

I urge you to read the full article.

Those benches mostly are for OpenCL, which I've been talking about. In that case, Iris Pro is way better than 750m. CUDA-based benches would be another story, since Iris Pro doesn't even have nVidia CUDA cores in it, so in that case 750m would, obviously, be better, since it's the only option.
However, I'd recommend to check if the required CAD software supports OpenCL and if so, just spend 200 bucks less and go with Iris Pro.
 
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MartinAppleGuy

macrumors 68020
Sep 27, 2013
2,247
889
If your CAD apps use OpenCL for computing, than Iris Pro will beat the **** out of 750m, so don't listen to the post above this one. 750m is much better for gaming. And that's true for gaming only.

But Autocad uses a lot of system ram; that keyed with the Iris Pro also using system ram will lead to lesser prermance. You need 16Gb of RAM if you want integrated graphics and run high end pro apps; why not just buy the 750m.

----------

Nop, not really.... here you go :

http://www.anandtech.com/show/6993/intel-iris-pro-5200-graphics-review-core-i74950hq-tested/17

Iris pro is wiping the floor with the 650M.

I urge you to read the full article.

But none of that matters if Iris Pro has no VRAM. The 1Gb of VRAM on the 750m will defiantly help.
 

yjchua95

macrumors 604
Apr 23, 2011
6,725
233
GVA, KUL, MEL (current), ZQN
Okay, before you buy an iMac, I suggest you do some homework on this:

Are the apps you're using OpenCL intensive or CUDA-assisted? If they're OpenCL, save your cash and go for an Iris. Keep in mind that Iris is shared with system memory. If they're CUDA-assisted, go for the NVIDIA.

Do those apps support multithreading? The i7 processor, on average, performs better a similarly-clocked or even faster i5 when running apps that support multithreading. And in RAM-intensive tasks, the i7 performs, on average, 20-30% better than an i5.

Proof: http://www.cpu-world.com/Compare/594/Intel_Core_i5_i5-4670K_vs_Intel_Core_i7_i7-4770S.html

The i5-4670K operates at 3.4GHz, and the i7-4770S (the same one in the high end 21.5" iMac) operates at 3.1GHz.

In this case, when running RAM intensive tasks, the i7 beats that i5 by around 22%. It's 13% better than the i5 in multithreaded tasks.
 

kaellar

macrumors 6502
Nov 12, 2012
441
17
But Autocad uses a lot of system ram; that keyed with the Iris Pro also using system ram will lead to lesser prermance. You need 16Gb of RAM if you want integrated graphics and run high end pro apps; why not just buy the 750m.
Having 1gb less RAM available and looking at the performance increase of 2 to 5-6 times, or have that additional RAM and.. that's it? What a tough choice :D
But none of that matters if Iris Pro has no VRAM. The 1Gb of VRAM on the 750m will defiantly help.
No it won't.
 

cirus

macrumors 6502a
Mar 15, 2011
582
0
Both CPUs have iris pro. Both have the 128 MB L4. I'd imagine even if you got the 750m model you could disable the 750m when using an OpenCL app and enable it if you need Cuda.
CAD is DX based on the 2013+ versions

11-AutoCAD-3D.png


The 750m will be stronger.
2D performance according to the same review is generally the same (probably held back by the CPU).
 

IA64

macrumors 6502a
Nov 8, 2013
552
66
Both CPUs have iris pro. Both have the 128 MB L4. I'd imagine even if you got the 750m model you could disable the 750m when using an OpenCL app and enable it if you need Cuda.

Any hint on switching between the Iris and dedicated GPU ?
 

MartinAppleGuy

macrumors 68020
Sep 27, 2013
2,247
889
Having 1gb less RAM available and looking at the performance increase of 2 to 5-6 times, or have that additional RAM and.. that's it? What a tough choice :D

No it won't.

It does. Iris Pro on the entry level iMac gets 25fps. On my iMac with the 1Gb of GDDR5 VRAM (750m) I get between 72-100fps on the same settings(maxed out). That is a maximum of 4X; I would call that a difference, wouldn't you?!?

----------

Both CPUs have iris pro. Both have the 128 MB L4. I'd imagine even if you got the 750m model you could disable the 750m when using an OpenCL app and enable it if you need Cuda.
CAD is DX based on the 2013+ versions

Image

The 750m will be stronger.
2D performance according to the same review is generally the same (probably held back by the CPU).

The iMac with the 750m has Iris Pro & 128Mb of DRAM as well?

----------

Having 1gb less RAM available and looking at the performance increase of 2 to 5-6 times, or have that additional RAM and.. that's it? What a tough choice :D

No it won't.

It is a fact that the 1Gb of GDDR5 VRAM what comes with the 750m is a LOT (I mean a LOT) faster than an integrated GPU that uses DDR3 RAM (that is used by the system too), and has 128Mb DRAM.

----------

No matter how you look at it, integrated graphics can never beat discrete graphics.

Go for the GT750M.

If you use AutoCAD or anything else from Autodesk, you'll also want to consider the i7, because the i7 has 8 threads, compared to the i5's 4.

And according to CPU-world.com, on average, i7s perform around 30% better than a similarly clocked i5, or higher-clocked i5 in multithreaded tasks or apps that support multithreading.

Thanks for the info on the increase in CPU performance on i5>i7.
 

kaellar

macrumors 6502
Nov 12, 2012
441
17
It does. Iris Pro on the entry level iMac gets 25fps. On my iMac with the 1Gb of GDDR5 VRAM (750m) I get between 72-100fps on the same settings(maxed out). That is a maximum of 4X; I would call that a difference, wouldn't you?!?

FPS? Maxed out settings? In CAD APPS?? Are you even aware of what we discuss here, gamin' boy?
 
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Roman2K~

macrumors 6502a
Mar 11, 2011
552
16
Both CPUs have iris pro. Both have the 128 MB L4. I'd imagine even if you got the 750m model you could disable the 750m when using an OpenCL app and enable it if you need Cuda.

I'm not sure about that. The i7 option in the 21.5" model seems to be limited to the Intel HD 4600. Indeed, the only i7 matching the clocks listed in the specs (3.1 GHz up to 3.9 GHz) is the 4770S (see those results). On Intel's page, that processor doesn't have the Iris Pro but the 4600 instead.
 

super spud

macrumors member
Original poster
Nov 20, 2013
45
0
Nop, not really.... here you go :

http://www.anandtech.com/show/6993/intel-iris-pro-5200-graphics-review-core-i74950hq-tested/17

Iris pro is wiping the floor with the 650M.

I urge you to read the full article.


The iris iz better at graphics work? Is this to do with the opengl?

----------

yep. both of these don't support OpenCL so I guess, it's gonna be better for you to go with 750m.


What actually is opencl? This is getting complicated.....
 

kaellar

macrumors 6502
Nov 12, 2012
441
17
The iris iz better at graphics work? Is this to do with the opengl?
Iris Pro is better for GPU-based computing, not general 3d-graphics aka games and DX- or OpenGL-based software. And no, 750m iMac version DOESN'T have the Iris Pro, it has simple desktop HD4600 iGPU that's utterly useless.

What actually is opencl? This is getting complicated.....
Were you banned at Google? :)
OpenCL is an open-source API for computing tasks. Almost every CPU-heavy task could be adapted for OpenCL and thus use GPU's paralleled and what's important optimized units to take the load off the CPU and do the job way more effectively. But no, your CAD apps don't rely on OpenCL, they rely on DX, so you won't benefit from IrisPro's great OpenCL pefrormance at all.
 

yjchua95

macrumors 604
Apr 23, 2011
6,725
233
GVA, KUL, MEL (current), ZQN
I'm not sure about that. The i7 option in the 21.5" model seems to be limited to the Intel HD 4600. Indeed, the only i7 matching the clocks listed in the specs (3.1 GHz up to 3.9 GHz) is the 4770S (see those results). On Intel's page, that processor doesn't have the Iris Pro but the 4600 instead.

21.5" iMac
Low end: i5-4570R
High end: i5-4570S or i7-4770S

27" iMac
Low end: i5-4570
High end: i5-4670 to i7-4771
 

cirus

macrumors 6502a
Mar 15, 2011
582
0
1. How the hell did you figured that out? The graph doesn't even have both GPUs (Okay, desktop 640 GDDR5 performs similar to 750m since they are both the same chip, but still).
2. Is Autodesk AutoCAD the only CAD app that's used by every man on Earth? :confused:

It does. Iris Pro on the entry level iMac gets 25fps. On my iMac with the 1Gb of GDDR5 VRAM (750m) I get between 72-100fps on the same settings(maxed out). That is a maximum of 4X; I would call that a difference, wouldn't you?!?

----------



The iMac with the 750m has Iris Pro & 128Mb of DRAM as well?

----------



It is a fact that the 1Gb of GDDR5 VRAM what comes with the 750m is a LOT (I mean a LOT) faster than an integrated GPU that uses DDR3 RAM (that is used by the system too), and has 128Mb DRAM.

----------



Thanks for the info on the increase in CPU performance on i5>i7.

Sorry, got mixed up with the macbook pro.
 

super spud

macrumors member
Original poster
Nov 20, 2013
45
0
Ok done a bit more reading and ive decided that the iris pro will probably be ok. Most of my cad work is currently in 2d. However the government is rolling out proposals that construction design is now in 3d. So by purchasing the imac with 750m card in anyway be future proofing my machine? Because if thats the case an addition £150 over 3 years isnt too bad.

I would like to thank everyone for their input into this thread. Tomorrow is the big order day!!

Edit I just realised im asking the wrong question. Can anyone tell me if autocad uses open cl or quda? Their website says for 3d work you need a shader but nothing I understand.
 
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